U.S. patent application number 10/542556 was filed with the patent office on 2006-06-22 for electrooptical element.
Invention is credited to Stefan Balle, Thomas Fehn, Sven Poggel.
Application Number | 20060132900 10/542556 |
Document ID | / |
Family ID | 34442537 |
Filed Date | 2006-06-22 |
United States Patent
Application |
20060132900 |
Kind Code |
A1 |
Fehn; Thomas ; et
al. |
June 22, 2006 |
Electrooptical element
Abstract
An electrooptical element is disclosed, made from a crystal (4),
for an electrooptical modulator (EOM), for example, a Pockels cell,
comprising a housing (5), with the crystal (4) arranged therein in
the form of a vertical cylinder, the both end surfaces of which
form a front plane, for entry of a light beam and an outlet plane
(41), at a separation from the above, with an annular electrode (1)
in contact with each of the above and with a retainer, between the
housing (5) and both the outer region of the crystal (4) and the
two annular electrodes (1). The invention is characterized in that
the retainer is embodied as an O-ring (2), concentrically enclosing
each annular electrode (1) and forming a closed annular chamber
between itself and the housing (5), made from an
electrically-conducting material and a hardened sealing compound
(3), filling the annular chamber.
Inventors: |
Fehn; Thomas; (Kronach,
DE) ; Balle; Stefan; (Germering, DE) ; Poggel;
Sven; (Maisach, DE) |
Correspondence
Address: |
Jordan & Hamburg
122 East 42nd Street
New York
NY
10168
US
|
Family ID: |
34442537 |
Appl. No.: |
10/542556 |
Filed: |
September 30, 2004 |
PCT Filed: |
September 30, 2004 |
PCT NO: |
PCT/EP04/10949 |
371 Date: |
January 25, 2006 |
Current U.S.
Class: |
359/322 |
Current CPC
Class: |
G02F 1/0305
20130101 |
Class at
Publication: |
359/322 |
International
Class: |
G02F 1/00 20060101
G02F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 25, 2003 |
DE |
203 18 348.7 |
Claims
1. Electrooptical element made of a crystal for an electrooptical
modulator (EOM), comprising a housing, a crystal arranged therein
in the form of a vertical cylinder having two cover surfaces which
form a front plane for a light beam to enter and an exit plane
arranged at a distance therefrom and against each of which an
annular electrode is placed, a holder provided between said housing
on one side and both a lateral surface of said crystal and said two
annular electrodes on the other side, said holder comprising an
O-ring made of an electrically conducting material that extends
concentrically about each annular electrode and that forms a closed
annular space between it and said housing and comprises a hardened
filling compound that fills said annular space.
2. Element in accordance with claim 1, wherein said housing has a
case having a fill aperture for said filling compound.
3. Element in accordance with claim 1, wherein said filling
compound comprises a plastic.
4. Element in accordance with claim 3, wherein said plastic for
said filling compound comprises resins, epoxies, lacquers, waxes,
thermoplastics, elastomers, duromers, and/or acrylates.
5. Element in accordance with claim 2 wherein said filling compound
comprises a plastic.
6. Element in accordance with claim 1 wherein said electrooptical
modulator (EOM) comprises Pockels cell.
Description
BACKGROUND OF THE INVENTION
[0001] The invention relates to a generic electrooptical element
for the purpose of installation in an electrooptical modulator
(EOM), e.g. Pockels cell, with a housing, with the crystal arranged
therein as a vertical cylinder, e.g., circular cylinder or cuboid,
whose two cover surfaces form a front plane for a light beam to
enter and an exit plane arranged at a distance therefrom and
against each of which an annular electrode is placed, and with a
holder provided between the housing on one side and both the
lateral surface of the crystal and the two annular electrodes on
the other side.
[0002] Such elements are known. Since all crystals in
electrooptical elements have piezoelectric effects, during periodic
changes to the applied electrical field the elements demonstrate
mechanical elongations, that is, natural oscillations at natural
frequencies--so-called piezo resonances--, which cause an
additional change in the optical density and during the
transmission of the electrical control signal overlay the phase of
the light beam, which is very undesirable.
SUMMARY OF THE INVENTION
[0003] The object of the invention is to reduce these natural
oscillations.
[0004] This object is inventively attained, in a generic
electrooptical element by its features in that the holder comprises
an O-ring made of an electrically conducting material that extends
concentrically about each annular electrode and that forms a closed
annular space between it and the housing and comprises a hardened
filling compound that fills the annular space.
[0005] Due to the filling compound, the natural oscillations and
the resonant sharpnesses, if any, are advantageously reduced in a
surprisingly simple manner, which might be due to the filling
compound acting as a sound absorber.
[0006] When in one useful design the filling compound and the shape
of the annular space are selected such that the characteristic
acoustic impedance is matched to the electrooptical element, the
result is a maximum reduction in the natural oscillations, which is
an additional advantage.
One exemplary embodiment of the invention is described in greater
detail in the following using the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic section of an electrooptical element;
and
[0008] FIG. 2 is a sectional view taken along the line II-II with
FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0009] The electrooptical element in accordance with FIG. 1 has a
housing 5 with a crystal 4 arranged therein in the form of a
vertical circular cylinder and is intended for use in a transverse
EOM, e.g. a Pockels cell. Its two cover surfaces act as a front
plane for the entry of an entering light beam and as a parallel
exit plane 41 for the light beam arranged at a distance therefrom.
An annular electrode 1 is placed against the cover surfaces.
[0010] A holder for these parts (1, 4) is provided between the
housing 5 on the one side and both the lateral surface of the
crystal 4 and the two annular electrodes 1 on the other side, which
are provided with a connection 7.
[0011] This holder has an O-ring 2 made of an electrically
conducting material that extends concentrically about each annular
electrode 1 and that forms a closed annular space between it and
the housing. Furthermore, the case of the housing 5 is provided
with a fill aperture 6 via which a filling compound made of plastic
can be filled in the annular space so that it completely fills the
annular space and then hardens. In this manner the crystal 4 and
parts of the two annular electrodes 1, if these are not already
held by the O-ring, are fixed in the housing 5.
[0012] The natural oscillations of the crystals can be effectively
dampened by selecting the shape of the annular space and the
plastic. Resins, epoxies, lacquers, waxes, thermoplastics,
elastomers, duromers, and/or acrylates can be considered for the
plastics.
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